JP7355336B2 - Method for producing a thread mass derived from bagworm silk spun on the surface of a base material - Google Patents

Description

The present invention relates to a method for producing a thread mass made of silk threads by spinning scaffold silk threads onto the surface of a base material using bagworms.

Threads that make up insect cocoons and mammalian hair have been used as animal fibers for clothing and the like since ancient times. In particular, silk threads derived from silkworms, which are the larvae of the silk moth (Bombyx mori) (often referred to as "silkworm silk threads" in this specification), have excellent moisture absorption and desorption properties, moisturizing properties, and heat retention properties, and have a unique luster and smoothness. Even today, it is prized as a high-quality natural material because of its soft texture.

However, there are animal fibers in nature that have properties comparable to or better than silkworm silk. In recent years, research and development efforts have been underway to utilize animal fibers with such excellent properties as new natural materials.

One type of silk that has attracted attention is spider-derived silk (herein often referred to as "spider silk"). Spider silk has flexibility, stretchability, and high elasticity that is 5 to 6 times that of polystyrene, and is expected to be used as a medical material such as surgical suture thread, and as a special material such as disaster prevention ropes and protective clothing. (Non-patent Documents 1 and 2). However, spider silk cannot be mass-produced because it is difficult to raise large numbers of spiders or collect large amounts of silk from spiders, and the production cost is also high. Attempts have been made to solve this problem by causing hosts such as silkworms and E. coli to produce spider silk using genetic recombination technology (Patent Document 1 and Non-Patent Document 2). However, since the silkworms and Escherichia coli that produce spider silk are genetically modified organisms, they can only be reared and cultured in facilities equipped with designated equipment, which poses the problem of a heavy maintenance burden. Another problem is that the liquid spider silk protein expressed in E. coli needs to be converted into fiber, which increases the number of steps. Furthermore, the spider silk spun by genetically modified silkworms is currently only a few percent mixed with silkworm silk, and it is not possible to obtain 100% spider silk that can utilize 100% of the characteristics of spider silk. There are also problems.

By the way, there is an insect called the bagworm (basket worm, alias "bag worm"). Bagworms are the general term for moth larvae belonging to the order Lepidoptera and the family Psychidae, and they usually hide in spindle-shaped or cylindrical nests made of leaves and twigs entwined with thread, as shown in Figure 1A. It is known that they live with the nest throughout the entire larval stage, moving with the nest even when feeding.

The silk produced by this bagworm (often referred to as "bagworm silk" in this specification) has recently attracted attention as a new natural animal fiber material with superior properties to silkworm silk and spider silk. ing. For example, the elastic modulus of bagworm silk from Eumeta minuscula is 3.5 times that of silkworm silk, and 2.5 times that of Nephila clavata spider silk, boasting extremely strong strength (Non-Patent Documents 1 and 2) ). In addition, it not only has a luster and luster equal to or higher than that of silkworm silk, but because the cross-sectional area of each single fiber is only about 1/7 of that of silkworm silk, it has a finer grain and smoother texture than silkworm silk. Thin and light cloth can be made.

Bagworms also have advantages over silkworms and spiders in terms of breeding. Like silkworms, bagworms are herbivorous, so unlike carnivorous spiders, food is easy to procure and can be supplied stably. They also have advantages over silkworms even though they are herbivorous. For example, silkworms, in principle, only feed on fresh leaves of species belonging to the genus Morus (for example, M. bombycis, M. alba, and M. Ihou); The breeding area and breeding season depend on the source of mulberry leaves and when the mulberry leaves open. On the other hand, bagworms are broad-feeding and have low specificity for the leaves they feed on, and many species can feed on the leaves of various tree species. Therefore, feed leaves are easily available and breeding areas are not a concern. Additionally, depending on the species, evergreen leaves can also be used as food, making it possible to supply food throughout the year, unlike deciduous mulberry trees. Furthermore, since bagworms are smaller in size than silkworms, they require the same amount of rearing space as silkworms or less, and can be easily reared in large quantities. Therefore, breeding costs can be suppressed.

Furthermore, bagworms are superior to silkworms in terms of productivity. For example, silkworms spout a large amount of silk only when cocooning, and all larvae perform cocooning at the same time. As a result, the yarn harvesting periods overlap, resulting in concentrated labor periods. However, throughout the larval stage, bagworms repeatedly spin silk when nesting or moving. Therefore, by artificially adjusting the yarn harvesting period, the working period can be dispersed.

As described above, bagworm silk has properties superior to those of silkworm silk and spider silk, and has many advantages in terms of production, so it is expected to be a very promising new natural material.

However, bagworm silk also has some problems in its practical application. One of the issues is related to the characteristics of bagworm nests. The surface of bagworm nests always has foreign matter such as leaves and twigs attached. This is due to the bagworm's habit of incorporating surrounding twigs and leaves into the nest for camouflage during the nest construction and expansion process. In order to commercialize bagworm silk, these impurities must be completely removed. Conventionally, these impurities have been removed manually from the nests that have been built, or the nests have been immersed in warm water for a long time to soften them and remove the impurities. However, removing these impurities requires a huge amount of effort. In addition, existing techniques cannot completely remove contaminants, resulting in small amounts of leaflets mixed in in the final product, dyeing bagworm silk in light brown with pigments derived from contaminants, etc. There was a problem that only low quality products could be obtained. Although it is possible to perform decolorization using a base or acid for the purpose of removing pigments, this results in a significant deterioration in quality, such as loss of strength of bagworm silk.

In addition to the nest silk that makes up the bagworm's nest, there is also a type of silk called scaffolding silk. As shown in Figure 1B, this scaffolding silk is a silk thread that is spun by the bagworm as a foothold to prevent it from falling when it moves. The research results of the present inventors revealed that this scaffold silk is stronger than nest silk and has excellent mechanical properties. Furthermore, unlike nest silk, scaffold silk does not contain foreign substances such as leaves and branches. Therefore, if scaffolding threads can be collected and used, it will be possible to put them to practical use as bagworm silk threads.

But there are also problems. First, the scaffold yarn is usually spun in a zigzag pattern in the direction of movement, as shown in FIG. 2A. Bagworm silk is spun with a mixture of fiber components and glue-like proteins covering its surface, but scaffold silk is spun with the glue-like proteins (Fig. 2A: arrowheads in the large circle) at the zigzag-like folding points. Fixed to the surface of the base material. This fixation is so strong that strong tension is required to mechanically peel the scaffold silk from the substrate. In addition, in many cases, the scaffolding silk thread is torn and fragmented around the fixed part due to this operation. Additionally, bagworm movements are generally difficult to control and can return to the same location over and over again. As a result, as shown in FIG. 2B, the silk threads spun in a zigzag pattern become layered and intricately intertwined, making it even more difficult to recover them from the base material without damage. Therefore, until now, scaffolding silk spun onto a base material has not been effectively utilized as a natural fiber material.

WO2012/165477

Shigeyoshi Osaki, 2002, Journal of the Japan Textile Society (Textiles and Industry), 58: 74-78 Kuwana Y, et al., 2014, PLoS One, DOI: 10.1371/journal.pone. 0105325

The purpose of the present invention is to peel bagworm scaffolding silk threads spun onto a base material, which have conventionally been difficult to recover and cannot be used, from the base material using a weak force without damaging them, and turn them into a thread mass. The goal is to develop and provide methods for recovering and reusing waste.

In order to solve the above problems, the present inventors have conducted intensive research and found that by spraying or applying a wetting liquid such as ethanol, an aqueous solution, or an organic solvent to bagworm silk spun onto a base material, Compared to a negative control that did not use such a wetting solution, we were able to successfully peel bagworm silk from the substrate using only 15% less force without damaging the thread mass. The present invention provides the following based on the above method.
(1) A method for producing a mass of bagworm silk, comprising a wetting liquid application step of applying a wetting liquid to the bagworm silk spun on the surface of a base material, and a separation step of separating the base material and the bagworm silk, The wetting liquid is a pure substance or a mixture that exhibits a liquid state at at least 20° C. or higher and lower than 30° C. under atmospheric pressure and does not damage, denature, or dissolve fibroin protein, which is a fiber component of bagworm silk.
(2) The method according to (1), which includes a yarn spinning step of arranging bagworms on the surface of the substrate and causing the bagworms to spin yarn before the wetting liquid applying step.
(3) The method according to (2), further comprising a bagworm collection step of collecting bagworms together with their nests after the yarn spinning step and before the wetting liquid application step.
(4) The method according to any one of (1) to (3), comprising a washing step of washing the separated bagworm silk.
(5) The method according to any one of (1) to (4), comprising a scouring step of scouring the separated bagworm silk.
(6) The method according to any one of (1) to (5), wherein the wetting liquid is a pure substance or a mixture having a melting point below 20°C and a boiling point between 30°C and 300°C.
(7) The method according to any one of (1) to (6), wherein the wetting liquid is an aqueous solution or an organic solvent.
(8) A method for collecting bagworm silk spun on the surface of a substrate, the method comprising: applying a wetting liquid to the bagworm silk spun on the surface of the substrate; A pure substance that includes a separation step of separating silk threads, wherein the wetting liquid exhibits a liquid state at at least 20°C or higher and lower than 30°C under atmospheric pressure, and does not damage, denature, or dissolve fibroin protein, which is a fiber component of bagworm silk threads. or a mixture thereof.
(9) The method according to (8), wherein the wetting liquid is an aqueous solution or an organic solvent.
(10) Bagworm silk obtained using the method for producing a mass of thread according to any one of (1) to (7), or the method for collecting thread according to (8) or (9).
(11) A nonwoven fabric composed of bagworm silk obtained using the yarn mass production method according to any one of (1) to (7).
This specification includes the disclosure content of Japanese Patent Application No. 2018-158762, which is the basis of the priority of this application.

According to the bagworm silk thread mass production method of the present invention, it is possible to collect bagworm scaffold threads spun on the surface of a base material, which have conventionally been difficult to collect, with a weak force without fragmenting them. can.

A: This is an external view of a nest of a bagworm (Ominogamimushi). B: It is a diagram showing the silk-spinning behavior of the longhorn beetle when it moves. You can see how the bagworm advances while spinning scaffolding silk (arrowhead), and how it hooks its claws onto the spun bagworm silk (scaffolding silk) (thin arrow). A: A schematic diagram showing the state of the bagworm silk thread (scaffold silk thread) when the bagworm thread is spun while moving on the surface of the base material. As shown in the figure, the bagworm's scaffold silk exhibits a ladder-like zigzag shape. In the figure, the black arrow indicates the direction in which the bagworm moves while spinning threads. Furthermore, the figure inside the large circle is an enlarged view of the small circle, and the arrowhead inside the large circle represents a pasty protein. The scaffolding silk thread is fixed to the base material at the folding point of the zigzag section, which corresponds to the side plate of the ladder. B: A diagram showing the state of bagworm silk when the bagworm silk is spun onto a plastic plate. You can see how the bagworm silk is intricately intertwined, spun in a zigzag pattern. FIG. 3 is a diagram showing a process flow of the bagworm silk thread mass production method of the present invention. 3 is a diagram showing the results of a peel tension evaluation test conducted in Example 1. FIG. In the figure, (A) shows the test results of a negative control without wetting liquid, (B) shows the test results when water was applied, and (C) shows the test results when ethanol (99.5%) was applied. There is.

1. Bagworm silk thread mass production method 1-1. Concept The first aspect of the present invention is a method for producing a bagworm silk mass. The production method of the present invention is a method in which a wetting liquid is applied to the bagworm silk spun on the surface of a base material, and then the base material and the bagworm silk are separated, thereby obtaining a target mass of bagworm silk. . According to the method of the present invention, scaffolding silk, which has excellent physical properties but has not been used in the past because it was difficult to recover without causing physical damage, can be efficiently used without causing damage. can be recovered.

1-2. Definition of Terms The following terms frequently used in this specification are defined as follows.
As mentioned above, "bagworm" is a general term for moth larvae belonging to the order Lepidoptera and the family Psychidae. Bagworm moths are distributed all over the world, and all larvae (bagworms) spend their entire larval stage binding natural materials such as leaves and twigs with silk they spun, and live in nests wrapped in these materials. are doing. Furthermore, when moving, both species have the habit of spinning out scaffolding silk threads in the direction of travel that serve as footholds to prevent falling. Therefore, the bagworm used in this specification is a larva of a moth belonging to the family Mynodae, and as long as it has the above-mentioned habit, the type, age, and sex of the bagworm are not restricted. For example, the Minogatidae family includes Acanthopsyche, Anatolopsyche, Bacotia, Bambalina, Canephora, Chalioides, Dahlica, Diplodoma, Eumeta, Eumasia, Kozhantshikovia, Mahasena, Nipponopsyche, Paranarychia, Proutia, Psyche, Pteroma, Siederia, Striglocyrbasia, Taleporia, Theriodopteryx, Trigonodoma However, the bagworm used herein may be a species belonging to any genus. Moreover, the instar of the larva may be any instar from the first instar to the final instar. However, in order to obtain a large amount of bagworm silk in terms of mass, it is preferable to use large bagworms. For example, if the larvae are of the same species, the last instar larvae are preferable, and if the larvae are male and female, larger females are preferable. Also, within the family Minogatidae, larger species are more preferable. For example, large species of Eumeta japonica and Eumeta minuscula are suitable species for use in the present invention.

Although the bagworms used in the production method of the present invention are not limited, bagworms that retain nests are preferred. "Holding the nest" refers to a state in which the bagworm carries the nest. As mentioned above, bagworms live together with their nests, and only partially expose themselves outside the nest when feeding or moving, as shown in Figure 1B.In principle, bagworms do not leave the nest during the entire larval stage. Never expose your entire body. Generally, when a bagworm is artificially separated from its nest and its whole body exposed to the outside world, the naked bagworm will minimize its movement and promptly return to its nest in order to protect its body and keep warm. Start rebuilding. Therefore, the reason why bagworms that maintain nests are preferable is that they do not give priority to the spinning action of nest silk, but actively spin scaffolding silk, which is the object of the present invention.

As used herein, "silk thread" refers to a protein thread that is derived from insects and is spun by insect larvae and adults for the purpose of nesting, moving, fixing, cocooning, capturing food, etc. In this specification, when simply written as "silk thread", it means a widely general silk thread that does not specify the origin insect name, and when referring to silk thread derived from a specific insect, it refers to silk thread derived from a specific insect, such as silkworm silk thread or bagworm silk thread. The name of the organism of origin shall be added in front of the silk thread.

As used herein, "bagworm silk" refers to silk spun by bagworms. Bagworm silk herein includes single fibers, spun fibers, and aggregated fibers. A "single fiber" is a filament that is the smallest unit that constitutes a fiber component, and is also called a monofilament. Single fibers are mainly composed of fibroin protein. In their natural state, bagworm silk and silkworm silk are spun as difilaments in which two single fibers are bound together by the adhesive sericin protein. This difilament is called "spun yarn fiber." Bagworm nests and silkworm cocoons are composed of spun fibers. In addition, multiple spun fibers are combined into a single fiber bundle, which is called a "multifilament." Generally speaking, raw silk refers to these aggregated fibers. Furthermore, raw silk is treated with soap, lye, basic chemicals such as sodium carbonate and urea, and enzymes to remove sericin protein, and the silk thread is called a drawn thread.

There are two types of bagworm silk: scaffolding silk and nest silk. "Scaffolding silk" is a silk thread spun by bagworms for movement, as described above, and functions as a foothold to prevent falling from branches, leaves, etc. On the other hand, ``nest silk'' is silk that is spun to construct the nest, and is used by bagworms to bind leaves and branches, and to create a comfortable environment for the inner walls of the nest, which is the living area. The bagworm silk in the present invention is a scaffold silk for that purpose. Therefore, in this specification, unless otherwise specified, "bagworm silk" refers to scaffold silk.

As used herein, the term "thread mass" refers to a thread aggregate composed only of bagworm scaffold silk threads. Although bagworm nests are aggregates of bagworm silk, they do not fall under the thread mass of the present invention because they are usually composed of nest silk in addition to contaminants such as twigs and leaves. Although not limited to, the thread mass in this specification refers to an aggregate of scaffolding silk threads produced through some kind of artificial process without contamination by contaminants. For example, one in which bagworms are placed on a base material and spun is included. The state of the thread mass is not limited, but for example, one or more bagworm silk threads may be intricately intertwined to form a sheet like non-woven fabric, or it may be assembled in a state where it can be reeled. It may be in a collective state.

"Wetting fluid" refers to a pure substance or mixture that exhibits a liquid state at at least 20°C or higher and lower than 30°C under atmospheric pressure, and that does not damage, denature, or dissolve fibroin protein, which is a fiber component of bagworm silk. Therefore, pure substances that are in a state other than liquid in the above temperature range, strong acidic or strong basic solvents that denature proteins even in a liquid state, or mixtures such as solutions containing protease, etc. are not suitable for the present invention. Not suitable as a wetting fluid.

A "pure substance" refers to a chemical substance that has certain properties, and includes a simple substance consisting of a single element and a compound consisting of multiple elements. The pure substance in the present invention is usually a compound, although it is not limited thereto.

“Mixture” refers to a substance that is a mixture of multiple pure substances. For example, solutions.

The wetting liquid may be composed of any pure substance or mixture as long as the above conditions are met. For example, but not limited to, it has a melting point (MP) below 20°C and a boiling point (BP) above 30°C and below 300°C at normal temperature (25°C) and normal pressure (100kPa). Examples include compounds. Many compounds with such properties have the property of being a "solvent" that can dissolve other compounds as solutes.

Specific examples in which the wetting liquid is a compound will be listed below, but the wetting liquid in this specification is not limited to the following.

The wetting liquid may be a liquid consisting of polar molecules (polar solvent). For example, water (MP: 0℃; BP: 100℃), methanol (MP: -96℃; BP: 64.7℃), ethanol (MP: -117℃; BP: 78.3℃), 1-propanol (MP: - 127℃; BP: 97.2℃), 1-butanol (MP: -90℃; BP: 118℃), glycerin (MP: 17.8℃; BP: 290℃), formic acid (MP: 8.3℃; BP: 100.8℃) , protic polar solvents such as acetic acid (MP: 15℃; BP: 118℃) and butyric acid (MP: -7.9℃; BP: 164℃), and DMSO (MP: 18.5℃; BP: 189℃), acetonitrile ( MP: -48℃; BP: 81.6℃), acetone (MP: -94℃; BP: 56℃), dimethylformamide (MP: -61℃; BP: 153℃), dimethyl sulfoxide (MP: 19℃; BP : 189℃), tetrahydrofuran (MP: -108℃; BP: 66℃), and 1,1,1,3,3,3-hexafluoro-2-propanol (MP: -3.3℃; BP: 58.2℃) This includes aprotic polar solvents such as. It also includes ionic liquids. Note that the numerical values in parentheses for each compound are the melting point (MP) and boiling point (BP) at normal temperature and normal pressure (hereinafter, the same shall apply in this specification).

Further, the wetting liquid may be a nonpolar liquid (nonpolar liquid: nonpolar solvent) made of nonpolar molecules. For example, it includes oil and many organic solvents (low polar organic solvents) with some exceptions. Oil is a compound that is in a liquid state at normal temperature and pressure, and includes, for example, a fatty acid represented by the general formula R-COOH (wherein R is an alkyl group of 4≦C≦8). Specific examples of non-polar liquids include valeric acid (valeric acid: MP: -34.5°C; BP: 186°C), caproic acid (hexanoic acid: MP: -3°C; BP: 205°C), and enanthic acid (valeric acid: MP: -34.5°C; BP: 205°C). Butylic acid, heptanoic acid: MP: -7.5℃; BP: 223℃), caprylic acid (octanoic acid: MP: 16.7℃; BP: 239.7℃), pelargonic acid (nonanoic acid: MP: 11℃; BP: 247℃) ), palmitoleic acid (hexadecenoic acid: MP: -0.1℃; BP: 230℃), linoleic acid (octadecadienoic acid: MP: -5℃; BP: 229℃), linolenic acid (octadecadienoic acid: MP: -11℃; BP: 278℃) and fatty acids such as arachidonic acid (icosatetraenoic acid: MP: -49℃; BP: 169℃), hexane (MP: -95.3℃; BP: 68.7℃), toluene (MP: -95℃; BP: 110.6℃), chloroform (MP: -63.5℃; BP: 61℃), dichloromethane (MP: -95℃; BP: 39.8℃), 1,2-dichloroethane (MP: -35.7℃; BP: 83.4℃), trichlorethylene (MP: -86.4℃; BP: 87℃), acetone (MP: -94℃; BP: 56℃), diethyl ether (MP: -116℃; BP: 34.6℃), xylene (MP: -25℃; BP: 137℃), carbon tetrachloride (MP: -23℃; BP: 76.7℃), methyl acetate (MP: -98℃; BP: 57℃), and ethyl acetate (MP: -84℃; BP: 77℃), etc.

On the other hand, when the wetting liquid in this specification is a mixture, a specific example thereof is a solution. Solutions include, but are not limited to, solutions consisting of polar or non-polar liquids in which one or more different solutes are dissolved, colloidal solutions or sol in which colloids are dispersed in a liquid as a dispersion medium, and two or more different solutes. Examples include liquids (for example, mixed liquids of different polar liquids, etc.), or combinations thereof. Examples of the polar solution include an aqueous solution in which a solute is dissolved in water, a mixed solution of solvents such as ethanol and water, and the like. In the case of an aqueous solution, the solute is not limited. Examples include, but are not limited to, salts, sugars, surfactants, and the like. The salt is not limited, but salts with high solubility are preferred. Examples include sodium chloride salt, potassium chloride salt, sodium carbonate salt, sodium bicarbonate salt, and the like. In the case of a solution, there are no particular limitations on the concentration of the solute. For example, it may be solubility. There is no particular limitation in the case of a mixed solution. For example, if it is a mixture of ethanol and water, it can be 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 95%, or 99.5% ethanol. It's okay.

As mentioned above, the type of pure substance or mixture that constitutes the wetting liquid does not matter; however, in consideration of ease of handling (including waste liquid treatment, etc.), safety, and purchase cost, water (hot water and hot water) ), aqueous solutions, ethanol, or mixtures thereof, with aqueous solutions and ethanol being particularly preferred.

As used herein, the term "substrate" refers to a base for harvesting bagworm silk. By placing bagworms on the surface of this base material and moving them, bagworm silk is spun onto the surface.

The material constituting the base material is not limited as long as the bagworm silk can be fixed to the surface using the glue-like protein. For example, glass (including enamel), metal, synthetic resin (including thermoplastic resin, thermosetting resin, and synthetic rubber), ceramics, or paper or plant pieces (e.g., wood pieces), animal pieces (e.g., bone), (including shells, shells, and sponges). However, if the base material itself dissolves due to the wetting liquid used or reacts with the wetting liquid such as oxidation-reduction reaction, the method of the present invention, which collects the bagworm silk spun on the base material, may be difficult. It doesn't fit the purpose. Therefore, it is desirable that the material constituting the base material be insoluble and non-reactive with the wetting liquid used in the present invention. "Insoluble in wetting liquid" refers to the property of not being dissolved in the wetting liquid used in the present invention. Moreover, "non-reactive with a wetting liquid" refers to the property of not causing a chemical reaction with the wetting liquid used in the present invention. Therefore, the material of the substrate of the present invention may vary depending on the type of wetting liquid used. For example, if the wetting liquid is water or an aqueous solution, synthetic resins such as polyethylene, polypropylene, polystyrene, vinyl acetate, cellulose acetate, acrylic resin, and polycarbonate can be used, but if the wetting liquid is a low polar organic solvent, they can be used. Soluble polystyrene, vinyl acetate, cellulose acetate, acrylic resin, polycarbonate, etc. cannot be used. Glass, ceramics, polypropylene, etc., which are easily available, relatively inexpensive, and have low reactivity, are suitable as materials for the base material.

The thickness of the base material used in this step is not limited. It may be determined as appropriate, taking into account the manufacturing cost, rigidity, ease of processing in subsequent steps, etc. of the base material. For example, it is preferable that the average thickness of the base material is 0.5 mm or more, 0.6 mm or more, 0.7 mm or more, 0.8 mm or more, 0.9 mm or more, 1.0 mm or more, 1.2 mm or more, or 1.5 mm or more, and further 3.0 mm or less, It may be 2.8 mm or less, 2.5 mm or less, 2.2 mm or less, or 2.0 mm or less. If the base material is composed of a thin film with an average thickness of less than 0.5 mm, 0.4 mm, 0.3 mm, 0.2 mm, or 0.5 mm, the base material itself does not have the rigidity to maintain a constant shape. It may be placed on a suitable support.

In this specification, a "support body" is a member that can impart rigidity and/or shape to a base material by arranging the base material on its surface. The support is an optional component used in the method of the invention and can be used as desired. The material of the support is not particularly limited as long as it has enough rigidity to maintain a certain shape. Examples include glass, metal, plastic, synthetic rubber, ceramics, paper, plant pieces, and animal pieces.

The shape and size of the base material used in this step are not limited. The shape may be, for example, a sheet-like or plate-like planar shape, or a three-dimensional three-dimensional shape. is preferred. The surface condition of the base material is also not limited, but a smooth surface that allows bagworm silk to be easily separated is preferable to a rough surface that has a strong adhesion force to bagworm silk threads. The size of the base material can be adjusted as needed, but considering that the scaffolding silk is bagworm silk that is spun out as it moves, the lower limit is the size of the bagworm, which is equal to or larger than the body length of the bagworm. It is preferable that the For example, the major axis or major axis can be 1 cm or more, 2 cm or more, 3 cm or more, 4 cm or more, or 5 cm or more. On the other hand, although there is no upper limit to the size of the base material, if the long axis or long axis is 10 cm or more, 15 cm or more, 20 cm or more, 25 cm or more, or 30 cm or more, it is preferable to have a plurality of bagworms spout threads.

1-3. Method The process flow of this embodiment is shown in FIG. As shown in this figure, the method of this embodiment includes a wetting liquid application step (S0103) and a separation step (S0104) which are essential steps, a yarn spinning step (S0101) which is a selection step, a bagworm collection step (S0102), It includes a cleaning process (S0105) and a scouring process (S0106). Each process will be explained below in order of flow.

1-3-1. Thread Spinning Step The “thread spinning step” (S0101) is a step in which a bagworm is placed on the surface of a base material and a bagworm that causes the bagworm to spin yarn is placed together with the base material, and is a selected step in the present invention. This step is performed before the wetting liquid application step described below.

"Arranging the bagworm on the surface of the base material" refers to positioning the bagworm on the surface of the base material so that the bagworm can come into contact with the surface of the base material. For example, the bagworms may be placed directly on the installed base material, or the bagworms may be placed so that they can reach the base material by movement. A specific example of the latter is placing a bagworm on the bottom of a wide-mouth plastic container without a lid, and then capping the container with a base material. Bagworms prefer high positions, so they move along the sides of wide-mouthed plastic containers and, after reaching the bottom surface of the substrate, which corresponds to the container's ceiling, they move there and spin scaffolding silk threads. There are no particular limitations on the installation position of the base material from which the bagworm silk is spun. As mentioned above, it may be installed on the ceiling of the container or on the wall. In this way, if the base material is installed at a place other than the bottom part, even if the bagworm defecates, the feces will fall to the bottom part, which is convenient because the yarn spouting surface will not be contaminated with the feces.

Note that the type and number of bagworms to be placed does not matter. For example, one bagworm or a plurality of bagworms may be placed at a time on each base material on which bagworm silk is spun. Furthermore, the type and age of bagworms to be placed does not matter. When a plurality of bagworms are arranged, each individual may be of the same species and the same age, or bagworms of different types and ages may be mixed.

The period of this step is not particularly limited. Although the period of implementation depends on the type and age of the bagworms and the number of individuals used, in any case, it is usually sufficient to continue the application until the required amount is spun onto the substrate. As an example, when using one late-instar giant beetle to spout threads onto a circular substrate with a diameter of 9 cm, it will take more than 1 day, more than 2 days, more than 3 days, more than 4 days, more than 5 days, more than 6 days. , or can be spun for more than 7 days. The bagworm's scaffolding silk is spun out as it moves, as described above, so the amount of silk obtained is, in principle, proportional to the distance the bagworm moves. Therefore, the time required for the thread-spinning process is shorter if multiple bagworms are used to spin the thread, rather than by a single bagworm. Additionally, bagworms often stop spinning during this process because they continue to spin silk without feeding. In such a case, the bagworm can be replaced with a new bagworm and the yarn spinning process can be continued.

In order to increase the amount of yarn spun by bagworms per unit time, it is preferable that the temperature and humidity during this step be constant or have little change. The temperature should be around 20°C, e.g. 15°C to 25°C or 18°C to 22°C, and the humidity should be around 50%, e.g. 40% to 65% or 45% to 60%. is preferred. The light and dark periods during this step are not particularly limited, and may be only a light period, but periodic light and dark periods may be provided. For example, in a 24-hour period, the light period is 6 hours to 18 hours, 7 hours to 17 hours, 8 hours to 16 hours, 9 hours to 15 hours, 10 hours to 14 hours, 11 hours to 13 hours, or 12 hours. The period may be such that the remaining period is a dark period.

1-3-2. Bagworm collection process "Bagworm collection process" (S0102) is a process of collecting bagworms used in the yarn spinning process together with their nests, and is a selection process in the present invention. The purpose of this step is to separate and collect unnecessary bagworms from the base material after the yarn spinning step.

After the spinning process, the spun scaffolding silk and the bagworms that spun the scaffolding silk are mixed together on the base material. However, in the next wetting liquid application step, bagworms are not required in principle. Furthermore, when the liquid used in the wetting liquid application step is applied to bagworms, the bagworm silk may exhibit undesirable staining due to body fluids of the bagworms or extracts of dead leaves used for nests. Therefore, although this step is a selective step, it is preferable to perform it after the yarn spinning step.

The method for collecting bagworms from the substrate is not limited. Any method of separating bagworms from the substrate can be used. For example, bagworms that are in contact with the base material may be peeled off along with their nests. However, for the purpose of the invention, a method that can reduce damage to bagworm silk as much as possible is preferred. For example, bagworms may be induced to spontaneously detach from the substrate. A specific example of this method is to take advantage of the above-mentioned property of bagworms to move to high places and turn the base material, which had been placed on the ceiling of the container, upside down so that it becomes the bottom surface. After the bagworms have been moved to the side of the container, the substrate can be collected. Another example is a method of heating the base material. Since bagworms spontaneously detach from the substrate in order to escape from high temperatures, the substrate may be collected after movement. The heating temperature may be room temperature or higher, as long as it does not damage the bagworm silk and does not melt the base material. For example, 30℃ or higher, 33℃ or higher, 35℃ or higher, 38℃ or higher, 40℃ or higher, 42℃ or higher, 45℃ or higher, 48℃ or higher, or 50℃ or higher, and 80℃ or lower, 75℃ or lower, 70℃ The temperature may be below 65°C, below 60°C, or below 55°C.
Note that the collected bagworms can be reused in the production method of the present invention after being fed.

1-3-3. Wetting liquid application process The "wetting liquid application process" (S0103) is a process of applying a wetting liquid to the bagworm silk spun on the surface of the base material, and is the most important essential process in the present invention.

The method of applying the wetting liquid is not particularly limited. Any method can be used as long as the bagworm silk on the surface of the substrate is sufficiently wetted with the wetting liquid. Examples include a method in which a wetting liquid is sprayed, jetted, or applied onto the surface of a base material on which bagworm silk has been spun, and a method in which a base material on which bagworm silk has been spun is immersed in a wetting liquid.

After applying the wetting liquid, it is preferable to hold it for a predetermined period of time. This is to ensure sufficient time for the wetting liquid to penetrate between the base material and bagworm silk. The "predetermined time" here is not particularly limited. It depends on the amount of wetting liquid applied and the application method, but usually 1 second to 1 hour, 1 minute to 40 minutes, 2 minutes to 30 minutes, 3 minutes to 20 minutes, 4 minutes to 15 minutes after application. Alternatively, 5 to 10 minutes is sufficient.

The temperature of the wetting liquid used in this step is not particularly limited as long as it does not damage, denature, or dissolve the bagworm silk. Typically room temperature ranges, e.g. 1°C to 35°C, 5°C to 32°C, 10°C to 30°C, 12°C to 27°C, 15°C if the wetting liquid has a melting point below 1°C and a boiling point above 35°C. The temperature may be between 18°C and 25°C or between 18°C and 20°C. However, in general, the higher the temperature of the wetting liquid, the higher the reactivity of the wetting liquid, so it is preferable that the temperature of the wetting liquid is high in this step as well. For example, if the wetting liquid is an aqueous solution, under atmospheric pressure, 35°C or higher, 38°C or higher, 40°C or higher, 42°C or higher, 45°C or higher, 48°C or higher, 50°C or higher, 52°C or higher, 55°C or higher, 58℃ or higher, 60℃ or higher, 62℃ or higher, 65℃ or higher, 68℃ or higher, 70℃ or higher, 72℃ or higher, 75℃ or higher, 78℃ or higher, 80℃ or higher, 82℃ or higher, 85℃ or higher, 88℃ Preferably, the temperature is 90°C or higher, 92°C or higher, 95°C or higher, and 98°C or higher. Note that the wetting liquid can be heated in advance before this step and/or during this step.

1-3-4. Separation Step The “separation step” (S0104) is a step of separating the base material from the bagworm silk spun on its surface after the wetting liquid application step, and is an essential step in the present invention. The method for separating the base material and bagworm silk is not particularly limited. Since the bonding force between the base material and the bagworm silk is reduced by the wetting liquid application step, the two can be separated with a relatively weak tension. For example, a method in which the end of the bagworm silk thread is grasped and peeled off from the base material, a method in which air or liquid is sprayed at high pressure on the bonding surface of the base material and the bagworm silk thread, and a method in which the base material is fixed The bagworm silk thread can be removed by suction as described above, or the base material is immersed in a liquid and then the liquid is made to flow by shaking the base material or stirring the liquid, and the liquid pressure generated at that time is used to separate the two. Examples include a method of separating. When the liquid is used in this step, the liquid is preferably the wetting liquid used in the wetting liquid application step, although it is not limited. Particularly suitable is water. Through this step, it is possible to obtain bagworm scaffolding silk spun on the surface of the substrate, which was difficult to recover without damaging it using conventional methods.

1-3-5. Washing Step The "washing step" (S0105) is a step of washing the bagworm silk separated in the separation step. This step is a selection step and may be performed as necessary.

The wetting liquid used in the wetting liquid application process remains on the surface of the bagworm silk obtained after the separation process. If the wetting liquid used is a solution or a low polar organic solvent, if it dries and sticks to the surface of bagworm silk, it may cause deterioration or discoloration of bagworm silk over time. Therefore, in this step, it is preferable to completely remove the used wetting liquid by washing. In addition, in this step, even if some of the feces is attached to the bagworm silk, it can be removed at the same time.

In this step, the cleaning liquid used for cleaning is not limited. When the wetting liquid used is a polar liquid, an aqueous solution, or a colloidal solution, the suitable liquid as the cleaning liquid is water (including hot water). Further, when the wetting liquid used is a non-polar liquid such as a low-polar organic solvent, other highly volatile solvents having high affinity with the low-polar organic solvent are suitable as the cleaning liquid. For example, when toluene or benzene is used in the wetting liquid application step, other xylene or ethanol can be used as the cleaning liquid.

The washing method is not limited as long as it can remove the wetting liquid used in the wetting liquid application step from the bagworm silk. The bagworm silk may be sprayed with a cleaning liquid or dipped in the cleaning liquid.

There is no limit to the number of washes. It can be done once or multiple times. As used herein, "multiple times" refers to, for example, 2 to 20 times, 2 to 15 times, 2 to 10 times, 2 to 7 times, 2 to 5 times, 2 to 4 times, or 2 to 3 times. Generally, it is preferable to perform washing multiple times. When washing is performed multiple times, the washing liquid used each time may be the same or different. Further, the cleaning methods may be the same or different. After washing, it may be left to dry naturally, or the washing liquid may be separated and removed by centrifugation using a dehydrator or the like.

1-3-6. Scouring process The "scouring process" (S0106) is a process of scouring the thread mass made of bagworm scaffold silk produced in this process. This step is a selection step and may be performed as necessary.

"Scouring" refers to removing sericin-like adhesive substances (glue-like proteins) from bagworm silk to obtain fibroin fibers.

The scouring method is not particularly limited as long as it is a method that can remove the adhesive substance without reducing the strength of the fiber components of the bagworm silk thread. For example, a method for refining silkworm silk can be applied. In the method for scouring silkworm silk, a sodium carbonate solution of 0.01 mol/L to 0.1 mol/L, 0.03 to 0.08 mol/L, or 0.04 to 0.06 mol/L is used as the scouring solution, but the same applies to the scouring step of this method. It can be used for. The obtained bagworm silk is boiled for 1 second to 1 hour, 5 seconds to 30 minutes, 10 seconds to 15 minutes, 20 seconds to 10 minutes, or 30 seconds to 5 minutes in the sodium carbonate solution, which is a scouring solution. do it.

In addition, when a scouring solution such as a sodium carbonate solution is used as the wetting liquid used in the wetting liquid application step, the same scouring solution is used in the subsequent scouring step, so a cleaning step before the scouring step is not necessary. Therefore, it is convenient. After the treatment in this step, cleaning may be performed in the same manner as in the cleaning step.

After the scouring process, the harvested bagworm silk may be dried. The drying method is not particularly limited as long as it can reduce the amount of wetting liquid, washing liquid, or scouring solution remaining on the bagworm silk without denaturing or deteriorating the scaffold silk. For example, the natural drying method (including sun drying) in which the dampening solution, cleaning solution, or scouring solution is vaporized by exposing it to the outside air, the air drying method in which hot or cold air is applied using a blower, and the drying method is carried out in a closed space with a dehumidifier. Examples include a dehumidifying drying method in which the wetting liquid, cleaning liquid, or scouring solution is left for a period of time, a heating drying method in which the wetting liquid, cleaning liquid, or scouring solution is evaporated and dried by heating, a reduced pressure drying method in which the liquid is degassed and evaporated using a vacuum pump, etc. in a container, or a combination thereof. .

2. Bagworm silk thread and nonwoven fabric composed of it 2-1. Overview A second aspect of the present invention is a scaffold silk of bagworm silk, and a nonwoven fabric made of the same. The bagworm silk thread and nonwoven fabric of the present invention are obtained using the thread mass production method of the first aspect.

2-2. Structure When the thread mass obtained by the method of the first aspect is spun on the surface of a base material without controlling the movement of bagworms, most of the threads have the form of a nonwoven fabric in which bagworm silk threads are overlapped vertically and horizontally on the surface of the base material. has been completed. Therefore, the product from which the bagworm silk threads on the surface of the base material are peeled off by the thread mass production method of the first aspect can be used as is as a nonwoven fabric. Furthermore, the scaffolding silk obtained by the method of the first aspect can be further made into a nonwoven fabric using an existing nonwoven fabric manufacturing method. Existing nonwoven fabric manufacturing methods include, but are not limited to, spunlace method and needle punch method.

On the other hand, if a cord is generated from bagworm silk on the surface of the base material and peeled off, or if the cord is pulled out from the peeled nonwoven fabric and reeled, a long bagworm silk can be obtained.

<Example 1>
(the purpose)
Using the yarn mass production method of the present invention, it will be verified through a peeling tension evaluation test that bagworm silk (scaffolding silk) spun on a base material, which was difficult to collect using conventional methods, can be easily harvested and recovered.

(material)
As bagworms, we used last-instar larvae of Ominomo moth (Ominogamina) collected from a fruit tree farm in Tsukuba City, Ibaraki Prefecture. In addition, an acrylic plate of about 30 cm ² was used as the base material.

(Method)
The bagworms used in the examples were fed a sufficient amount of food leaves until the day before the silk-spinning process.
Threads were spun onto the surface of the acrylic board, which was the base material, by placing bagworms on a vertically erected acrylic board and letting them climb up the wall of the acrylic board.

After sufficient bagworm silk has been spun on the surface of the acrylic plate, water (pure water), 30%, 50%, and 70% ethanol aqueous solutions, and 99.5% ethanol are applied to the evaluation target area using a syringe. A few drops of each were added. Note that the negative control was bagworm silk to which no wetting liquid was applied (sample to which no wetting liquid was applied).
Here, the peel tension evaluation test used in this example will be explained. As shown in Figure 2A, the bagworm scaffold silk exhibits a ladder-like zigzag shape. This scaffolding silk thread is fixed to the base material surface at the folding point ("in this specification, referred to as "zigzag block") corresponding to the horizontal board of the ladder indicated by the broken line ellipse in FIG. 2A. (denoted as "fixed point"). When peeling the scaffold silk thread, the tension shows a peak at the fixing point of each zigzag block because the largest force is required, but after peeling, it is not fixed to the base material until the next fixing point, so the tension decreases. Relax to an initial value of zero. Similarly, at the next fixed point, a large tension is required during peeling, but the initial value is returned immediately after peeling. This cycle is repeated between each zigzag block when the scaffolding silk is peeled off. In the peeling tension evaluation test, one end of the bagworm scaffold silk spun on the substrate surface was fixed to the load cell of a tensile testing machine, and then the bagworm silk was peeled off at a constant speed, and the change in tension was continuously recorded. By doing so, the process in which the adhesion at the fixed point is released and the zigzag-shaped scaffold threads are unraveled into a straight line can be measured as the relationship between peeling length (pulling distance) and tension.

After applying each wetting solution and confirming that the bagworm silk threads were sufficiently moistened, one end of the bagworm silk threads on each acrylic plate was pulled out and fixed to the load cell of a tensile tester. When the fixed bagworm silk thread was peeled off at a constant speed (100 μm/sec), the change in tension was continuously recorded using a load cell. A tensile testing machine (Shimadzu small tabletop testing machine EZ Test) was used for the measurement.

In this example, the total sum of all peak areas per zigzag block obtained in the peel test was divided by the peel length to calculate the peel energy per unit peel length. In order to minimize the influence of individual differences in the adhesive strength of the bagworms used in the yarn-spinning process, the results when each wetting solution was used were compared to the negative control (sample without wetting solution) of scaffold silk spun by the same individual bagworms. ), and evaluated and compared as a percentage (%) when the peeling energy of the negative control was set as 100.

(result)
The results are shown in FIG. 4 and Table 1.

In FIG. 4, the horizontal axis shows the peeling length (mm), and the vertical axis shows the peeling tension (N). As shown in Figure 4(A), the negative control required a relatively strong peeling tension of 0.003 to 0.004 N at each fixed point per zigzag block. On the other hand, when water was applied, as shown in FIG. 4(B), the peeling tension was about 0.001N, which was about 1/4 of that of the negative control. Furthermore, when ethanol (99.5%) was applied, the peeling tension was 0.0001 to 0.0002 N, which was dramatically reduced to about 1/20 to 1/40 of the negative control, as shown in Figure 4 (C). It became clear that

As shown in Table 1, when water was applied to the substrate and bagworm silk, the peeling energy was reduced to about 30% of that of the negative control. Furthermore, when ethanol (99.5%) was applied, the effect decreased to 6% of the negative control, which was found to be significantly more effective than water. This effect of ethanol was maintained over various concentrations even in the case of an aqueous ethanol solution, which is a mixed solution of ethanol and water, and it was confirmed that the effect was higher than that of water at all concentrations.

<Example 2>
(the purpose)
The ability of the thread mass production method of the present invention to be used with wetting liquids other than water and ethanol will be verified by a peeling tension evaluation test.

(Method)
The basic procedure and basic operations were the same as in Example 1. Here, the wetting liquid used is methanol (MeOH), which is a polar monohydric alcohol, 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP), which is a polar halogen-containing organic solvent, and polar Dimethyl sulfoxide (DMSO) is a sulfur-containing organic solvent, carbon tetrachloride is a low polar halogen-containing organic solvent, glycerin is a polar trihydric alcohol, and 0.05M aqueous sodium chloride solution (NaCl aq), and 0.05M aqueous sodium carbonate solution (Na₂C.O.₃aq) was used.

(result)
Table 2 shows the results.

As shown in Table 2, the application treatment reduced the peeling energy to 15% or less of the negative control for all wetting liquids. In addition, high effectiveness was confirmed in that both required less than half the peeling energy of water.
All publications, patents, and patent applications cited herein are incorporated by reference in their entirety.

Claims (9)

A method for producing a mass of bagworm silk, the method comprising:
a wetting liquid application step of applying a wetting liquid to the bagworm silk spun on the surface of the base material, and a separation step of separating the base material and the bagworm silk,
The wetting liquid is a pure substance or a mixture that exhibits a liquid state at at least 20° C. or higher and lower than 30° C. under atmospheric pressure and does not damage, denature, or dissolve fibroin protein, which is a fiber component of bagworm silk. 2. The method according to claim 1, further comprising a thread-spinning step of arranging bagworms on the surface of the base material and causing the bagworms to spin threads before the wetting liquid application step. 3. The method according to claim 2, further comprising a bagworm collection step of collecting the bagworms together with their nests after the yarn spinning step and before the wetting liquid application step. The method according to any one of claims 1 to 3, comprising a washing step of washing the separated bagworm silk. The method according to any one of claims 1 to 4, comprising a scouring step of scouring the separated bagworm silk. A method according to any one of claims 1 to 5, wherein the wetting liquid is a pure substance or a mixture having a melting point below 20°C and a boiling point above 30°C and below 300°C. The method according to any one of claims 1 to 6, wherein the wetting liquid is an aqueous solution or an organic solvent. A method for harvesting bagworm silk spun on the surface of a base material, the method comprising:
a wetting liquid application step of applying a wetting liquid to the bagworm silk spun on the surface of the base material, and a separation step of separating the base material and the bagworm silk,
The wetting liquid is a pure substance or a mixture that exhibits a liquid state at at least 20° C. or higher and lower than 30° C. under atmospheric pressure and does not damage, denature, or dissolve fibroin protein, which is a fiber component of bagworm silk. 9. The method of claim 8, wherein the wetting liquid is an aqueous solution or an organic solvent.

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